The present invention relates to an arm-rest adjustable in inclination, in particular for vehicles.
As is known many vehicles are provided with arm-rests adjustable in inclination.
An example of a traditional adjustable arm-rest is shown in FIGS. 32 and 33, which respectively show a perspective and a front view of the load-bearing frame.
In general, an arm-rest adjustable in inclination is provided with a load-bearing frame comprising a fixed part F, which is attached to the vehicle, and a movable part M, which is hinged to the fixed part F along a rotation axis X and defines by means of upholstery (not shown in the figures) the plane of the arm-rest.
The inclination of the plane of the arm-rest is adjusted by rotating properly the movable part M in relation to the fixed part F, between a lowered position (as shown in FIG. A), which generally corresponds with the movable part positioned horizontally, and a raised position (not shown), which generally corresponds with the movable part positioned vertically.
To such purpose, adjustable arm-rests traditionally have adjustment systems comprising a ratchet device. The latter is framed so as to allow the rotation of the movable part in steps upwards only and to keep the movable part in the position reached in the upward rotary movement.
More in detail, as one may observe in FIG. 34 (relative to a cross-section view along the plane C-C shown in the front view of FIG. 33), the ratchet device comprises a toothed portion D made on the movable part M and a pawl L, hinged to the fixed part and kept constantly engaged to the toothed portion D by an elastic element (not visible in FIGS. 32, 33 and 34). The pawl L may only disengage itself from the toothed portion D when the movable part M is rotated upwards.
During this movement, in fact, the movable part M itself contrasts the effect of the elastic element, disengaging the pawl L from the toothed wheel D.
The rotation downwards of the movable part M requires, on the contrary, that the ratchet device be deactivated.
To such purpose the system for adjusting the arm-rest comprises proper releasing means of the pawl (not shown in the attached figures), normally activable on command by the user by means of suitable levers.
A first limit of the adjustable arm-rests described above lies in the impossibility of fine adjustment of the inclination. The ratchet device enables adjustment (in steps) at predefined positions, the number of which is substantially equivalent to the number of teeth in the toothed portions. Once the excursion angle has been fixed (between the maximum and minimum inclination) for reasons of construction and solidity, it is not possible to increase the number of teeth. This significantly limits the adjustment possibilities, thereby making the arm-rest not always adaptable to the user's needs, to the detriment of perceived comfort.
A second limit is the noise of the system for adjusting the arm-rest. The steps of the ratchet device produce noises which may be annoying, giving the idea of malfunctioning and poor product quality.
A third limit is associated with the risk that the ratchet device, on account of wear or construction defects of the toothed portions, may not function correctly. It may happen in fact that in some adjustment positions, the movable part of the arm-rest does not remain stable, or that the movable part suddenly falls downwards. The blocking of the movable part on the fixed part is in fact entrusted to the engagement of toothed portions of limited extension.